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From: ziegast@eng.umd.edu (Eric W. Ziegast)
Newsgroups: comp.lang.perl
Subject: Re: A question on associative arrays
Message-ID: <1991May30.174847.907@eng.umd.edu>
Date: 30 May 91 17:48:47 GMT
References: <1991May30.134223.23225@Think.COM>
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In article <1991May30.134223.23225@Think.COM> sid@think.com (Sid Stuart) writes:
>
>I am writing a Perl application in which I would like to store
>into an associative array only if an entry for that key does
>not exist. The problem is I may come up with duplicate keys and
>I don't want to overwrite the contents of an entry. Is there a
>cheap way to find out if a key is in use? By cheap I mean other
>than using the functions "keys" or "each" to search through all
>the keys of the array.

   print defined($assoc{$key}) ? "$assoc{$key}\n" : "Key $key undefined\n";

So long as you don't set $assoc{$key} to a value (even ""), that entry
in the associative should be undefined.

Eric Z.
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| Eric W. Ziegast      Internet: ziegast@eng.umd.edu |
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